Intumescent silicate compositions



I v M moi brawing.

Patented Mar. 1, 1932 it 'f .Qnuemmsrnnonajior LocKroRr, .1-T-'Ew ironmnssrenon TO THE urson. GOMEA'NY, or;

c v anocxroa'r NEWUYORK, 1A conroanrron or, NEWYOBIK INTUMESGENT sILIcArE COMPOSITIONS I {present invention relates: to the) prov:ductionz of; porous or' *cellulan-materi alprofrducedrby-zintumescing compositions-containing silicate of soda as used fen-building and 7 11 similar pro ducts,xand ais aniimprovementup on athe rrinventions disclosed in: United States a:dIletters-PatenttorHoWard FaWeisset al.,'No. 151,628,206, Zdated wMay r10, 1927,-- ent1t1ed fMoldd :productaand;process: for: its manufacturey, andKemper'SlideH, No.:1 ,655,714,'

cchinez;and-rmethodz for- :making Wallboard;

a :wcenfi plasticcompositiona in which; the silicate i i: lot sodaiisrmixedwith an inorganicfiller. .The a {improwementsrarefurtherdlrected; 111 a-composition rotithiskind toward making avail- 13113167 33 aifillerccomponent,. materials 1 I not i hitherto ipracticablefor useinthe-makmg of amhigh grade; commercial; article such; as a Water and moisture resisting wallboard.

To these; land othen ends i'the rinventifon re- FiuIlY idesoribed, evthe novel features '1 being :pointedroutjilfi the claims atlthe end of this specification;

ea-wmethodzisz describedwherein awsolution of "-1 5a silicatewofsoda ismixed inrcertainsspeciiied eproportmns, such; as =one,-part1-.-alkali sodium. iasilicatewraith;aboutatwosparts tof powdered i syfil-ler iwhich maybedolomite,ilimestonegslate,

" 1': gether,-,:if a preferred, With; paper zliners or Fiacingsait liepuffed. by-heatinto-va cellular i. ingand ior-a other, ip'urposes.

5o -.Underrthisprocess{asvhitherto kit is Application filed fJanuary '18," 1929 Serial No. 333,530. 1 i

a :--ashes andthelike; arThe:intumescent-plastic I io thus producediis -passed :between heated necessary to comminute the limestone used as a fillerby prolonged and extensive-grindingto dimensions not easilyattainable; in

flordinarygrinding mills} By the'use ofymy mpresent invention such extraordinary 'Land costly;grinding is obv iated in the production of a commercially successful product. Further, my present inventionqmakes; avail- 1: able as filler material such cheap substances as commonsaniground slag, ground shale, o r "even common clay. Ordinarily all of: the before mentioned filler substances (limestone excepted) do not produce a product sufiiciently Water and moisture resistant to be always commercially useful as a Wallboard inbuildings and for other purposes.

In carrying out my inventiomI have found that by incorporating the chemical 1 compound, Well known as light-magnesium car.-

-bonate, into themix of silicateof soda sold- :tlon and the powdered inorganicfiller, I can produce intumesced, porous; build-ingmaterials without excessively; 'grindingk limestone and can also use comminute'd materials other than limestone, e. g., sand,, ground slag;

y -ground sha1e,"etc. and'can use less concensidesrxin certaln improvements; and comblna- I iltlOnSw f. parts all-as -wwill berherelnaftermore centrated silicate of sodaisolution "thanwhas been-possible heretofore and atlthe sameitime produce;v a satisfactory! Water and :moisture resistant pro duct suitable for Wallboards for f buildingsand' forother purposes. *Thelight In therinventions-of thepatents just menti0ned',-:anexaminationiofwhich is suggested,

magnesium carbonate that I use occurs, in nature, and is also madeby mlXlIlg magnsium sulfate and sodium CHiIbQIliLtGptO- "gether Wlth" suitable precautions. The light magnsiumcarb'onate may also be mad i other Waystoo numerousto mention. -However,- whether: the light magnesium carbonate that I use} in this inventlon is; ofnatural occurrence or-is artificially prepared, .it is essential that-it consistofa-Very bulky mass u-of-minute-particles and usually as a mixture of" very small crystals; and amorphous. apar- :ticles. Ispe'cifically wish to point out that the light magnesiumcarbonate of commerce, rather than the heavy magnesium carbonate, issuitable for the accomplishment of-lthis invention." l

I Annex-act chemical ctormula'for lightmag- ;:1'1e'sium :carbona-te :can ,not :be given, because 7 its formula seems to vary to some extent, de-

pending upon different methods by which it is 1produced. The substance is known and de nitely recognized in thechemical trade by the name flight magnesium carbonate, however, and, any substance commonly called by thisname isisuitable forlithe purposes of the present invention, notwithstanding 7. any slight variations in its chemicalformulat tainable both in a pur'egrade,'s uitable for medical use,'and in a technical or, commercial grade. The technical, ,or commercial grade of light magnes um carbonate 1s satisfactory for the; purposesof the present in vention. Lightmagnesium carbonate is readthe light "carbonatei That is, a givenvve ight of light magnesium carbonateoccupies ama- T j-terialgreater volume than the same ,yveight of heayy magnesium carbonate.="

a In the practice of my invention I prefer,

' at present, to take sand, crushed slag, crushed I i material crushed-to a'fine'n-e'ss' sothat 7 5%,

shale, crushed limestoneor other inorganic more'or less, of the material will pass through a mesh screen, The de'gree-of fineness offiller is very much 'coaiflserthanthat which it has beenpossible to use hithertoin the V. ,7 prior art, wherein over 95%'ofi groundlime stone must pass throughra- 200 mesh screen a in order toproduce aconiineroially water' and mois ture resistant building composition.

as wallboard'is tobe produced,;while'in the present invention such restriction is no longer efl'ective. Takin'g the relatively coarser tially dry sand, 10"parts of lightmagnesium i carbonate, and 300 parts of a 485 B: silicate j-of soda solution; and mixthese" materials in i next: subject the intumesced material to: the 1' action of hot air in an 'ovenm In general the 7 temperatureof thb-ven'should approx};

, obta1ined.' 1-:

1; fillers" above *mehtioned, I incorporate them a with light magnesium carbonate and silicate 'of' soda solution'by meansof any suitable weighing and mixing 'devices. (For example,

I may'take by Weight 790 parts of substan heating operation as described inth United 1 States patents aforesaid is particularly important in securing a commercially Water and ing to the present inventiomlthe total amount of silicate of soda $248.5 Baum may be reduced below the amount hitherto used in p I I the, riorart, thus reducing thecostof the 'Lightmagnesium" carbonateis commonly ob-f' finis ed? product. The use-cau ht magnecheaper silicate of soda having a'specific gravityless than the 48.5 Baum silicate; of

soda heretofore customarily used, while yet 7 i producing asatisfactory Water and moisture ily-distinguishable from the heavy ma'gnesie um-c'arbonatejby the much greater bulk of resistant product-(such aswallbbardlwith a relatively inexpensive filler other than lfin ely ground limestone "composition,whnincorporated with silicate {of soda solution {and an inorganic filler-, I'am not able to say definitely at this time. It is possible, due to the" extreme fineness offthe particles of; the light magnesium carbonate that a chemical o r*quasichemical reaction takes place, wholly or in {part between 'the light magnesium carbonate and the silicate of sodato form a more or les's water insoluble magnesium silicate.' i a On the other hand, ,th

I action between the light" magnesium carbonate fAlSO, in lthe prior art the choice; of a' fille'ri has been commerciallyrestricted to limestone "if a waterandflm'oistu resistant product such and the silic'ateof soda solution may be a physical ones] The enormoussurface area of the very minute particles of the light magnesium carbonatelmay" ab'soi 'bTthe silicate of soda strongly= so thatf aycementing effect is j "lhere may be other explanations of this aterproofing reaction in buildingimaterials between light magnesium carbonate and silidate of soda {solution incorporated therein, but I amnot no'wabl'e to decide' What the a correct explanation.g

' While the above 7 example "shows "a general Way the' nature of my invention; I do u I I not inany way restrict myself to these given mixture in -any: suitable device 'to for'ma a building composition. 1 'For exa'mple, I'may place this'mixbetweensheets ofi'liners com a posed ofpaperfibersfto form a Wallb'oardi; "Ithen intumesce the building composition by any suitable heatingl'device' such as by passage" through steam heated platens; I"

ingredients or proportions; For "example,

'I may use more of thelight m'agne siumfcarbonate and a less concentrateds'ilic ate ofsoda solution, and -at-thegsamefti'me I may crush mixture may then ;be molded and intumesced by heat in the manner set forth abovein connection 7 with the piseeding example." i 01', again,"I niay prefer-to use 'amixtu're of coarse sand, and finesa'nd with varying amounts of light] magnesium carbonate "and varying 5 Waterproofing re- -12 passing a 36 mesh "screen,"f12 1 parts by 7 ,weight of; lightfmagnesium "carbonatef'and '317parts by weight of slimmer-soda; solutionghaving agravity "of 42 .5 Baum." This mate-410 Fahrenheit,- and i the' intu'mesced 'buildingmaterial-50f, this invention-should v besubjectedto thisl heatforsulficient time to" expel substantially all ofthe moisture pres-f L ente. g., for 20'minutes,-mor e or less."v This 65,

amounts of silicate of soda solutions of difierent concentrations and of different ratios of sodium and silicon. Again, I may prefer to use a mixture of different particulate inorganic fillers, e. g., a mixture of sand and ground limestone, with light magnesium carbonate, and silicate of soda solutions, etc., etc. It will be seen from. the examples above given that the light magnesium carbonate constitutesonly a minor part of the intumescent mixture, and usually amounts to only a few I per cent. of the quantity of filler employed.

I claim as my invention: 1. A composition of matter comprising a thoroughly intumesced combination of silicate of soda, an inorganic filler and a minor quantity of light magnesium carbonate.

2. An intumesced, porous composition of matter containing a filler having a relatively small proportion of light magnesium carbonate mixed therewith and silicate of soda solution.

3. An intumesced, porous composition of matter containing sand, light magnesium carbonate and silicate of soda.

4:. An intumesced, porous composition of matter containing. substantially dry sand, partly as occurring in nature, and partly artificially crushed, light magnesium carbonate 9 and silicate of soda solution.

5. An intumesced, porous, composition of matter containing a particulate inorganic filler, light magnesium carbonate and silicate of soda solution.

6. A method of making an intumesced porous building material which comprises making a mixture of particulate, inorganic fillers, light magnesium carbonate and silicate of soda solution of less density than 48.5 B.,

o and. heating such mixture to cause it to intumesce. t

7. The method of making an intumesced porous building material which comprises mixing a ground inorganic filler with sodium silicate and light magnesium carbonate and heating the resulting mixture to cause it to intumesce.

8. The method of making an intumesced i porous building material which comprises mixing ground limestone with light magnesium carbonate and sodium silicate and heating the resulting mixture to cause it to intumesce. HUGH M. SPENCER. 

